Publishers provide books for readers having a wide range of reading capabilities. In particular, publishers provide books having content that includes words and sentence complexities appropriate for readers with specific reading capabilities. For example, children's books may include short words and simple sentences, while textbooks targeted to university graduate students may include technical terms and complex sentences.
Additionally, books published for readers of different reading capabilities often do not include the same core content. Rather, books of different reading levels include different content with words and sentence complexity that correspond to the reading capabilities of a target audience. In order to provide similar content in books with different reading levels, a publisher may need to incur the expense and dedicate resources to publishing multiple versions of a book, where each version includes the same core content. For instance, a publisher may publish a full version of a book written by Fyodor Dostoevsky, as well as an abridged version of this book.
In an education context, schools, school districts, universities, and other educational entities may purchase different books for each level of reading capability of their students. In some cases, classes may have students with a wide range of reading capabilities and the reading capabilities of the students may change as a school year progresses. Educational entities typically provide a number of books of certain reading levels to classes based on estimates of the number of students at each reading level. However, the actual number of students at a particular reading level may differ from the estimates of the educational entity. Thus, at any given time, an educational entity may provide a class with too few books of one reading level and too many books of another reading level. As a result, some students may receive materials that are inappropriate for their reading capabilities and some materials may go unused.
Further, in some cases, electronic versions of books may be provided to readers. However, since an electronic version of a book corresponds directly to a printed version of the book, the reading level of the electronic version of the book is the same as the reading level of the printed version of the book. Consequently, electronic versions of the book including content at other reading levels are unavailable.